Biodegradable and/or compostable articles of manufacture

ABSTRACT

Articles of manufacture formed from starch ester biodegradable and/or compostable compositions and blends of starch ester biodegradable and/or compostable compositions with biodegradable and/or compostable polymer compositions. The articles of manufacture may include but are not limited to inks, paints, compost bag, laminate bags, agricultural films, binder for earthenware, landscape piles or spikes, bottles, strands, sheets, films, packaging materials, pipes, tubes, lids, cups, rods, laminated films, sacks, bags, cutlery, pharmaceutical capsules, foams, granulates and powders.

This application claims the benefit of priority to U.S. Application No.63/393,506 filed on Jul. 29, 2022, U.S. Application No. 63/393,509 filedon Jul. 29, 2022, and U.S. Application No. 63/393,515 filed on Jul. 29,2022, the entire contents of each of the applications are incorporatedherein by reference.

This disclosure relates to biodegradable and/or compostable articles ofmanufacture formed from bio-based starch mixed ester biodegradableand/or compostable compositions and blends of the bio-based starch mixedester biodegradable and/or compostable compositions with biodegradableand/or compostable polymer compositions, where the bio-based starch isprovided from non-petroleum based sources, i.e., from plant or bio-basedsources.

BACKGROUND

The accumulation of plastic waste in the environment is an increasingsocietal concern. Different solutions and disposal routes are beingexplored to reduce the amount of plastic reaching the environment andlandfills such as recycling, composting, and energy recovery viaincineration. One approach to reduce the pollution associated withfossil-derived plastics is through the development and use of bio-basedand biodegradable and/or compostable polymers.

To that end, there is a continuing investigation into making articles ofmanufacture formed from biodegradable polymers and/or polymers that arecompostable.

SUMMARY

In general, this disclosure is directed to articles of manufactureformed from starch ester biodegradable and/or compostable compositionsand blends of starch ester biodegradable and/or compostable compositionswith biodegradable and/or compostable polymer compositions. The articlesof manufacture may include but are not limited to inks, paints, compostbag, laminate bags, agricultural films, binder for earthenware,landscape piles or spikes, bottles, strands, sheets, films, packagingmaterials, pipes, tubes, lids, cups, rods, laminated films, sacks, bags,cutlery, pharmaceutical capsules, foams, granulates and powders.

The articles of manufacture may also include, but are not limited to:

-   -   (1) Films and sheet formed by extrusion, casting, rolling,        inflation, etc.    -   (2) Lamination and coatings on paper, sheet, film, nonwoven        fabric, etc.    -   (3) Additives to be incorporated into paper during the paper        making process to impart special functions to the paper and        paper products.    -   (4) Additives to be incorporated into non-woven fabric during        its manufacturing process to impart special functions to the        non-woven fabrics and their products.    -   (5) Aqueous emulsions or suspensions for use with paints, inks,        and the like.    -   (6) Solid molded products such as landscaping piles produced by        injection molding, extrusion molding, blow molding, transfer        molding, compression molding, etc.

The articles may be made by various methods known in the art such as,but not limited to, extrusion, injection molding, compression molding,filming, blow molding, vacuum forming, thermoforming, extrusion molding,co-extrusion, foaming, profile extrusion, combinations thereof, as wellas other known and contemplated methods.

As noted above, the articles may be derived from bio-based starch mixedester biodegradable and/or compostable compositions. The bio-basedstarch mixed ester biodegradable and/or compostable compositions mayhave the following general formula:

wherein n=1 to 20 and y=1 to 20; wherein R₁ is acetic, propionic,butyric, hexanoic, maleic, succinic, phthalic, hexenyl succinic,octenyl, and stearic anhydride and mixtures thereof and wherein R₂ isC₂₋₂₄ carboxylic acid, and is desirably lauric acid, myristic acid,palmitic acid, stearic acid, arachidic acid, linoleic acid, linolenicacid, steridonic acid, oleic acid, and mixtures thereof. In someinstances, R₂ is lauric acid, stearic acid, oleic acid and mixturesthereof.

The starch mixed ester may be formed by reacting at least one anhydride,at least one acid, and a bio-based starch in the presence of a catalystto form a starch mixed ester biodegradable and/or compostablecomposition. In some aspects, the at least one anhydride and at leastone acid may be first reacted to form a mixed acid anhydride, which maythen be reacted with a bio-based starch in the presence of a catalyst toform a starch mixed ester biodegradable and/or compostable composition.Advantageously, the reactions occur with bound and/or free water beingpresent in the starch and/or the catalyst.

In some instances, one or all of the starch, fatty acid, and anhydrideare derived from bio-based sources, i.e., from plants rather than frompetroleum sources and to that end, it is contemplated that methods ofmaking the described starch mixed ester compositions and the resultingstarch mixed ester compositions are free of petroleum sourced starch,fatty acid, and anhydride.

In some instances, a first mixed acid anhydride and a second mixed acidanhydride are separately formed and, after formation mixed togetherprior to reacting the mixture with a starch. In this regard, a firstanhydride and a first acid may be reacted to form a first mixed acidanhydride, a second anhydride and a second acid may be reacted to form asecond mixed acid anhydride. While the first and second anhydride maydiffer, generally it is the same and, in those instances, it may beacetic anhydride. Typically, the first and second acids differ.Thereafter, the first anhydride and second anhydride may be mixedtogether and then reacted with a starch in the presence of a catalyst toform a starch mixed ester biodegradable and/or compostable composition.

In other instances, a first mixed acid anhydride, a second mixed acidanhydride, and a third mixed acid anhydride are separately formed and,after formation mixed together prior to reacting the mixture with astarch. In this regard, a first anhydride and a first acid may bereacted to form a first mixed acid anhydride, a second anhydride and asecond acid may be reacted to form a second mixed acid anhydride, and athird anhydride and a third acid may be reacted to form a third mixedacid anhydride. While each of the first, second, and third anhydride maydiffer, generally it is the same and, in those instances, it may beacetic anhydride. Typically, each of the first, second, and third acidsdiffer. After formation of the first, second, and third mixed acidanhydride, they are mixed together and then reacted with a starch in thepresence of a catalyst to form a starch mixed ester biodegradable and/orcompostable composition.

In another embodiment, an acid is mixed with an anhydride to form ananhydride mixture. Separately, an anhydride, which may or may not be thesame as that used to form the anhydride mixture, is reacted with astarch in the presence of a catalyst, which is typical a base such as ahydroxide, e.g., sodium hydroxide. The product is dehydrated and reactedwith the anhydride mixture during with the starch is esterified to forma starch mixed ester biodegradable and/or compostable composition, whichmay be washed and dried to form the desired product.

In yet another embodiment, an acid, an acid anhydride, a catalyst, andstarch may be combined in a single reactor where the starch is bothdehydrated and esterified to form the starch mixed ester biodegradableand/or compostable composition.

In some instances, a first mixed acid anhydride and a second mixed acidanhydride are separately formed and, after formation mixed togetherprior to reacting the mixture with a starch. In this regard, a firstanhydride and a first acid may be reacted to form a first mixed acidanhydride, a second anhydride and a second acid may be reacted to form asecond mixed acid anhydride. While the first and second anhydride maydiffer, generally it is the same and, in those instances, it may beacetic anhydride. Typically, the first and second acids differ.Thereafter, the first anhydride and second anhydride may be mixedtogether and then reacted with a starch in the presence of a catalyst toform a starch mixed ester biodegradable and/or compostable composition.

In other instances, a first mixed acid anhydride, a second mixed acidanhydride, and a third mixed acid anhydride are separately formed and,after formation mixed together prior to reacting the mixture with astarch. In this regard, a first anhydride and a first acid may bereacted to form a first mixed acid anhydride, a second anhydride and asecond acid may be reacted to form a second mixed acid anhydride, and athird anhydride and a third acid may be reacted to form a third mixedacid anhydride. While each of the first, second, and third anhydride maydiffer, generally it is the same and, in those instances, it may beacetic anhydride. Typically, each of the first, second, and third acidsdiffer. After formation of the first, second, and third mixed acidanhydride, they are mixed together and then reacted with a starch in thepresence of a catalyst to form a starch mixed ester biodegradable and/orcompostable composition.

In still other embodiments, an acid anhydride is mixed with a starch,and a catalyst under suitable conditions and for a period of time todehydrate the starch and any water that may be present in conjunctionwith the catalyst. In one instance, the acid anhydride may be aceticanhydride, the catalyst may be a 50% aqueous NaOH solution, and thestarch may be provided from cornstarch which may be a high amylosecornstarch. Thereafter, an acid, which may be a C₂₋₂₄ carboxylic acid,and an additional amount of the acid anhydride are added to thereactants under suitable conditions to esterify the starch to form thestarch mixed ester biodegradable and/or compostable composition.Thereafter, the resulting mixture may be water washed to removeunreacted reaction products to provide a resulting water-washed starchmixed ester product, which may be dried. It is also contemplated thatthe water-washed starch mixed ester product may be further washed withan alcohol such as ethanol to remove unreacted acid to provide analcohol-washed starch mixed ester product, which may be dried.Alternatively, the dehydrated product may be directed to an extruder forfurther processing optionally with additives or other biodegradableand/or compostable polymers, as will be explained in more detail below.As yet another alternative, it is contemplated that the water andalcohol washed product may be dried and then blended with one or morebiodegradable and/or compostable polymers.

The resulting starch mixed ester biodegradable and/or compostablecompositions (whether water-washed, alcohol-washed, or otherwise) mayhave any suitable physical form such as but not limited to liquid,powder, particles, resin, etc.

The articles may also be formed from biodegradable and/or compostablecompositions made from blends of bio-based starch mixed esters andbiodegradable and/or compostable polymers and methods of making them.The blend may include from 20% to about 90% of the described starchmixed esters and from about 10% to about 80% of at least one otherbiodegradable and/or compostable polymer. The blends may be prepared bymixing or melt processing using, for example, an extruder.

The bio-based starch mixed esters have been described above. Thebiodegradable and/or compostable polymer in the blend is generally astarch biodegradable and/or compostable polymer and may includepolylactide (PLA), poly(hydroxybutyrate) (PHB), polycaprolactone (PCL),polyhydroxy butyrate valerate (PHB-V), poly(β-hydroxyalkanoate) (PHA),Poly(1,4-butylene succinate) (PBS), polybutylene adipate terephthalate(PBAT), poly(vinyl alcohol) (PVA), cellulose-based ester derivatives ora mixture thereof.

The blend composition may include optional additives selected from thegroup consisting of extenders; fillers; wood derived materials; oxidesof magnesium, aluminum, silicon, and titanium; alkali and alkaline earthmetal salts; lubricants; mold release agents; acid scavengers;plasticizers; UV stabilizers; coloring agents; flame retardants;antioxidants; thermal stabilizers; and mixtures thereof.

As used in this description, the term “biodegradable” refers to aplastic or polymeric material that will undergo at least partialbiodegradation by living organisms (microbes) in anaerobic and aerobicenvironments (as determined by ASTM D5511), in soil environments (asdetermined by ASTM D5988), in freshwater environments (as determined byASTM D5271 (EN 29408)), or in marine environments (as determined by ASTMD6691 or ISO14852). The biodegradability of biodegradable plastics canalso be determined using ASTM D6868, ASTM D6400, and European EN 13432.

As used in this description, the term “compostable” refers to abiodegradable material that may be broken down into only carbon dioxide,water, inorganic compounds, and/or biomass, which does not leave anyvisible or toxic residue. In some embodiments, articles formed from thedescribed compositions may be biodegradable or “compostable” asdetermined by ASTM D6400 and/or ASTM D6868 for industrial and/or homecompostability.

The details of one or more examples are set forth in the accompanyingdrawings and the description below. Other features, objects, andadvantages will be apparent from the description and drawings, and fromthe claims.

All percentages used or recited in this description refer to a percentby weight, unless specifically stated otherwise. Other aspects andadvantages of this invention will be appreciated from the followingdetailed description.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a flow diagram illustrating an exemplary proposed process formaking the described bio-based starch mixed ester biodegradable and/orcompostable composition.

FIG. 2 is a flow diagram illustrating an alternative exemplary proposedprocess for making the described bio-based starch mixed esterbiodegradable and/or compostable composition.

FIG. 3 is a flow diagram illustrating an alternative exemplary proposedprocess for making the described bio-based starch mixed esterbiodegradable and/or compostable composition.

FIG. 4 is a flow diagram illustrating an alternative exemplary proposedprocess for making the described bio-based starch mixed esterbiodegradable and/or compostable composition.

FIG. 5 is a flow diagram illustrating an alternative exemplary proposedprocess for making the described bio-based starch mixed esterbiodegradable and/or compostable composition.

FIG. 6A shows the results of a thermogravimetric analysis (TGA)performed on a sample of a starch acetate stearate that has been madeand water washed according to the method shown and described inconnection with FIG. 5 .

FIG. 6B shows the results of a thermogravimetric analysis (TGA)performed on a sample of a starch acetate stearate that has been madeand ethanol washed according to the method shown and described inconnection with FIG. 5 .

FIG. 6C shows the results of a thermogravimetric analysis (TGA)performed on a sample of a high amylose cornstarch used to make thestarch acetate stearate tested in FIGS. 6A and 6B.

FIG. 7A shows the ¹H-NMR analysis of a sample of a starch acetatestearate that has been made and water washed according to the methodshown and described in connection with FIG. 5 .

FIG. 7B shows the ¹H-NMR analysis of a sample of a starch acetatestearate that has been made and ethanol washed according to the methodshown and described in connection with FIG. 5 .

FIG. 7C shows the ¹H-NMR analysis of a sample of a high amylosecornstarch used to make the starch acetate stearate tested in of FIGS.7A and 7B.

FIG. 8A shows the ¹³C-NMR analysis of a sample of a starch acetatestearate that has been made and water washed according to the methodshown and described in connection with FIG. 5 .

FIG. 8B shows the ¹³C-NMR analysis of a sample of a starch acetatestearate that has been made and ethanol washed according to the methodshown and described in connection with FIG. 5 .

FIG. 8C shows the ¹³C-NMR analysis of a sample of a high amylosecornstarch used to make the starch acetate stearate tested in of FIGS.8A and 8B.

FIG. 9 shows the results of a Cobb 120 test performed according to ASTMD3285-93 that compares uncoated 86 GSM Kraft paper and coated 86 GSMKraft paper which was coated with various coatings using various coatingweights.

DETAILED DESCRIPTION

As noted above, this disclosure is directed to articles of manufactureformed from starch ester biodegradable and/or compostable compositionsand blends of the starch ester biodegradable and/or compostablecompositions with biodegradable and/or compostable polymer compositions.The articles of manufacture may include but are not limited to inks,paints, compost bag, laminate bags, agricultural films, binder forearthenware, landscape piles or spikes, bottles, strands, sheets, films,packaging materials, pipes, tubes, lids, cups, rods, laminated films,sacks, bags, cutlery, pharmaceutical capsules, foams, granulates andpowders.

The articles of manufacture may also include, but are not limited to:

-   -   (1) Films and sheet formed by extrusion, casting, rolling,        inflation, etc.    -   (2) Lamination and coatings on paper, sheet, film, nonwoven        fabric, etc.    -   (3) Additives to be incorporated into paper during the paper        making process to impart special functions to the paper and        paper products.    -   (4) Additives to be incorporated into non-woven fabric during        its manufacturing process to impart special functions to the        non-woven fabrics and their products.    -   (5) Aqueous emulsions or suspensions for use with paints, inks,        and the like.    -   (6) Solid molded products such as landscaping piles produced by        injection molding, extrusion molding, blow molding, transfer        molding, compression molding, etc.

The articles of manufacture may be formed in any known manner suitableto achieve the desired shape and function of the sought after articles.For example, the articles may be made by various methods known in theart such as, but not limited to, extrusion, injection molding,compression molding, filming, blow molding, vacuum forming,thermoforming, extrusion molding, co-extrusion, foaming, profileextrusion, combinations thereof, as well as other known and contemplatedmethods.

As noted above, the articles may be manufactured from starch mixed esterbiodegradable and/or compostable compositions and blends of starch mixedester biodegradable and/or compostable compositions with biodegradablepolymer and/or compostable compositions. Descriptions and methods ofmaking such follow. Referring to FIG. 1 , a proposed flow diagram of aproposed process for making the described bio-based starch mixed esterbiodegradable and/or compostable composition is shown. In general, ananhydride and an acid are combined with a starch, which in someinstances is a bio-based starch, and an esterification catalyst in areactor. It will be appreciated that the anhydride and acid can addedseparately to the reactor or, as shown in FIG. 1 , the anhydride andacid can first be reacted to form an acid anhydride, which is thencombined with the starch in the reactor. In some instances, additionalanhydride may be added to the reactor before or during the reactionprocess.

Suitable anhydrides may include acetic anhydride, propionic anhydride,butyric anhydride, hexanoic anhydride, maleic anhydride, succinicanhydride, phthalic anhydride, hexenyl succinic anhydride, octenylanhydride, and stearic anhydride and mixtures thereof. The anhydride inone instance is acetic anhydride.

The acid may be a carboxylic acid and may be one or more of a C₂₋₂₄carboxylic acid and mixtures thereof. In some cases the carboxylic acidmay be C₁₀ to C₂₄ and mixtures thereof, and in some instances may belauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid,linoleic acid, linolenic acid, steridonic acid, oleic acid, and mixturesthereof. In some instances, the carboxylic acid is lauric acid, stearicacid, oleic acid and mixtures thereof.

It is contemplated that the carboxylic acid may be a saturated or anunsaturated fatty acid. Advantageous examples of carboxylic acids mayinclude fatty acids such as lauric acid, myristic acid, palmitic acid,stearic acid, arachidic acid, linoleic acid, linolenic acid, steridonicacid, oleic acid, and mixtures thereof. In some instances the carboxylicacid is lauric acid, stearic acid, oleic acid and mixtures thereof.

As one example where the anhydride and acid are first mixed together andreacted, acetic anhydride and lauric acid may be reacted according tothe proposed mechanism shown below.

It will be appreciated that, in equilibrium, the following compounds maybe present: acetic anhydride, lauric acid, acetic lauric anhydride,acetic acid, and lauric anhydride. Further, depending on ratio of theanhydride and the acid, it is believed that the ratio of the resultingmixed acid anhydride (i.e., acetic lauric anhydride) changes.

It will be appreciated that the reaction of acetic anhydride with othercarboxylic acids noted above will proceed according to the reactionscheme noted above and will produce the respective mixed acidanhydrides. Thus, the reaction of acetic anhydride with stearic acidwill produce, in equilibrium, acetic anhydride, stearic acid, aceticstearic anhydride, acetic acid and stearic anhydride. Similarly, thereaction of acetic anhydride with oleic acid will produce, inequilibrium, acetic anhydride, oleic acid, acetic oleic anhydride,acetic acid and oleic anhydride. With the above reaction scheme in mind,it should be noted that reference or mention of a mixed acid anhydrideas the reaction product of an anhydride and an acid will include, forexample, with specific reference to the reaction product of aceticanhydride and lauric acid, each of lauric acid, acetic acid, aceticanhydride, acetic lauric anhydride, and lauric anhydride

Regarding the starch, as noted above, the described compositions areformed using a bio-based starch. As used in the specification andclaims, the term “bio-based” refers to a starch source that is anon-petroleum source. In other words, “bio-based” refers to starchprovided from a plant source and is meant to exclude fossil basedstarches. The bio-based starch or a derivative thereof, may be referredto as a starch or a starch component. It will be understood that theterm starch or starch component when used in the specification and theclaims refers to a bio-based starch or derivative thereof, unlessspecifically noted otherwise.

Starch (C₆H₁₀O₅)_(n) is a mixture of linear (amylose) and branched(amylopectin) polymers. Amylose is essentially a linear polymer ofα(1→4) linked D-glucopyranosyl units. Amylopectin is a highly-branchedpolymer of D-glucopyranosyl units containing α(1→4) linkages, withα(1→6) linkages at the branch points. The starch or starch component maybe based on any native starch having an amylose content of 0 to about100% and an amylopectin content of about 100 to 0%. In some instances,the amylose content is greater than about 50% or from about 60% to about90%, or from about 65% to about 85%, or about 70% to about 80%. In someembodiments, the amylose content is from about 60%, 61%, 62%, 63%, 64%,65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%,79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, or about 90%. Insome instances, the amylopectin content is from about 10% to about 40%,or from about 15% to about 35%, or about 20% to about 30%. In someembodiments, the amylopectin content is about 10%, 11% 12%, 13%, 14%,16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%,30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38% 39%, or about 40%.

The starch component may be derived from barley, potato, wheat, rye,oat, pea, maize, corn, tapioca, sago, rice, cassava, arrachaca,buckwheat, banana, kudzu, oca, sago sorghum sweet potato, taro, yam,fava, lentil, or other tuber-bearing or grain plant. It may also bebased on starches prepared from native starches by oxidizing,hydrolyzing, crosslinking, cationizing, grafting, or etherifying.

It is known that starch contains entrained or endogenous water ormoisture in amounts between about 13 wt. % and about 20 wt. %. As aresult, if starch is dried in a conventional manner, i.e., using heat,there exists a flammability hazard, which the described method avoids.In addition, it is believed that drying in the conventional manner maystrengthen the hydrogen bonds in the starch molecule, making it moredifficult for the subsequent esterification reaction to proceed. To thatend, the described process contemplates removing bound and free water byreacting the starch with an anhydride (e.g., acetic anhydride) at roomtemperature to form an acid (e.g., acetic acid) and to reducesubstantial starch degradation.

Referring back to FIG. 1 , the starch mixed ester compositions may beprepared in the presence of an esterification catalyst. Suitableesterification catalysts may be selected from the groups of (i)hydroxides and/or mineral acid salts or organic acid salts or carbonatesof any metals selected among alkali metals, alkaline-earth metals andamphoteric metals, (ii) organic interlayer transition catalysts and(iii) amino compounds, such as those exemplified below.

Alkali metal hydroxides such as sodium hydroxide, potassium hydroxide,lithium hydroxide, etc.; salts of organic acids and alkali metals suchas sodium acetate, sodium propionate, sodium p-toluenesulfonate, etc.;alkaline-earth metal hydroxides such as barium hydroxide, calciumhydroxide, etc.; salts of organic acids and alkaline-earth metals suchas calcium acetate, calcium propionate, barium p-toluenesulfonate, etc.;salts of mineral acids such as sodium phosphate, calcium phosphate,sodium bisulfite, sodium bicarbonate, potassium sulfate, etc.; acidicsalts or hydroxides of amphoteric metals, such as sodium aluminate,potassium zincate, aluminum hydroxide, zinc hydroxide, etc.; carbonatessuch as sodium carbonate, potassium bicarbonate, etc. Typically, thealkali metal hydroxides may be provided as aqueous solutions, e.g., a50% aqueous solution of NaOH.

Amino compounds such as dimethylaminopyridine, dimethylaminoacetic acid,etc.

Quaternary ammonium compounds such as N-trimethyl-N-propylammoniumchloride, N-tetraethylammonium chloride, etc.

By varying the amount of the mixed acid anhydride, the amount of starch,the amount of the catalyst, as well as the reaction conditions, starchmixed esters with different degrees of substitution may be prepared. Theratio of the types of ester groups present on the starch mixed ester mayvary greatly. When two different ester groups are present, they may bepresent in a range of about 20:1 to about 1:20.

A proposed reaction formula of the esterification of the starch with themixed anhydrides may be depicted as:

wherein x=1 to 20 and y=1 to 20; wherein R₁ is from acetic, propionic,butyric, hexanoic, maleic, succinic, phthalic, hexenyl succinic,octenyl, and stearic and mixtures thereof and wherein R₂ is from C₂₋₂₄carboxylic acid, and in some cases may be C₁₀ to C₂₄, and in someinstances may be lauric acid, myristic acid, palmitic acid, stearicacid, arachidic acid, linoleic acid, linolenic acid, steridonic acid,oleic acid, and mixtures thereof. In some instances, R₂ is from lauricacid, stearic acid, oleic acid and mixtures thereof.

It will be appreciated that the starch mixed ester includes at least twoand in some cases three different ester residues attached to the samestarch molecule. To that end, the starch mixed ester includes both long-and short-chain carboxyl acid components. As an example, it iscontemplated that the starch mixed ester may include a mix of acetateand laurate, a mix of acetate and stearate, a mix of acetate and oleate,or a mixture of each mixt.

The total degree of substitution of the esterified starch may range fromabout to 2.9, and in some instances is greater than 1.0. Accordingly, insome instances, it is contemplated that the total degree of substitutionmay be from about 1.5 to about 2.9 or about 1.8 to about 2.7 or about2.0 to about 2.5 or about 2.2 to about 2.4. In some embodiments, thetotal degree of substitution may be about 1.5, 1.6, 1.7, 1.8, 1.9, 2.0,2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, about 2.9, or within any rangethat may be formed from each of the preceding values. It is expectedthat the starch mixed ester compositions will exhibit a desired balancein mechanical properties, water resistance, processability and the rateof biodegradation.

Generally, the degree of substitution of the acetate is from about 0.5to about 2.4, or about 0.6 to about 2.3 or about 1.0 to about 2.2, orabout 1.6 to about 2.2. In some instances, the degree of substitution ofthe acetate is from about 0.5, 0.6, 0.7, 0.8, 1.0, 1.1, 1.2, 1.3, 1.4,1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, about 2.2, or within any range thatmay be formed from each of the preceding values. The degree ofsubstitution of the other ester residue (i.e., from the carboxylic acid,e.g., laurate, stearate, oleate), may be from about 1 to about 2.5 orabout 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3,2.4, or about 2.5. In some instances, the degree of substitution of theother ester residue (i.e., from the carboxylic acid, e.g., laurate,stearate, oleate), may be from about to about 1.0, or about 0.01, 0.02,0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.4, 0.5, 0.6, 0.7,0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1,2.2, 2.3, 2.4, about 2.5, or within any range that may be formed fromeach of the preceding values.

The resulting starch mixed esters may have a glass transitiontemperature ranging from about 125° C. to about 165° C., In someinstances, the resulting starch mixed esters have a glass transitiontemperature of about 125° C., 126° C., 127° C., 128° C., 129° C., 130°C., 131° C., 132° C., 133° C., 134° C., 135° C., 136° C., 137° C., 138°C., 139° C., 140° C., 141° C., 142° C., 143° C., 144° C., 145° C. 146°C., 146° C., 148° C., 149° C., 150° C., 151° C., 152° C., 153° C., 154°C., 155° C., 156° C., 157° C., 158° C., 159° C., 160° C., 161° C., 162°C., 163° C., 164° C., or about 165° C.

According to one embodiment, the mixed acid anhydride is combined withthe starch to disperse the starch, after which the catalyst may be addedso that the reaction occurs for a period of time at a temperaturebetween about 100° C. to about 200° C., or about 130° C. to about 155°C. The resulting product may be cured in water (which may be effectiveto separate unreacted acid anhydride and fatty acid), after which thecured product may be pulverized, washed, neutralized, and dehydrated.The dehydrated product may then be dried to provide a dried product. Inaddition, it is contemplated that the dried water washed product may bewashed with alcohol, which will remove unreacted fatty acid, and thendried. Alternatively, the dehydrated product may be directed to anextruder for further processing optionally with additives or otherbiodegradable and/or compostable polymers, as will be explained in moredetail below. As yet another alternative, it is contemplated that thewater and alcohol washed product may be dried and then blended with oneor more biodegradable and/or compostable polymers.

The optional additives may include one or more members selected from thegroup consisting of extenders; fillers; wood derived materials; oxidesof magnesium, aluminum, silicon, and titanium; alkali and alkaline earthmetal salts; lubricants; mold release agents; acid scavengers;plasticizers; UV stabilizers; coloring agents; flame retardants;antioxidants; thermal stabilizers; and mixtures thereof.

Turning now to FIG. 2 , a proposed flow diagram of an alternativeproposed process for making a bio-based starch mixed ester biodegradableand/or compostable composition is shown. In this process, the anhydrideand one or more carboxylic acids may be reacted to form a mixed acidanhydride, which is thereafter mixed and reacted with the bio-basedstarch and catalyst to form bio-based starch mixed ester biodegradableand/or compostable composition. In some examples, the anhydride isacetic anhydride and the carboxylic acid is lauric acid, stearic acid,oleic acid and mixtures thereof, which after reaction will form a mixedacetic-fatty anhydride. Thus, the resulting mixed acid anhydride mayinclude acetic-lauric anhydride, acetic-stearic anhydride, acetic-oleicanhydride, and mixtures thereof.

In one embodiment, a first mixed acid anhydride and a second mixed acidanhydride are separately formed and, after formation mixed togetherprior to reacting the mixture with a starch and a catalyst. In thisregard, a first anhydride and a first acid may be reacted to form afirst mixed acid anhydride. In addition, a second anhydride and a secondacid may be reacted to form a second mixed acid anhydride. While thefirst and second anhydride may differ, generally they are the same and,in those instances, it may be acetic anhydride. It is contemplated thatthe first and second acids differ. Thereafter, the first mixed acidanhydride and second mixed acid anhydride may be mixed together and thenreacted with a starch in the presence of a catalyst to form a starchmixed ester biodegradable and/or compostable composition.

As an example, the first and second anhydride may include acetic,propionic, butyric, hexanoic, maleic, succinic, phthalic, hexenylsuccinic, octenyl, and stearic anhydride and mixtures thereof. The firstand second anhydride may be the same or different. In some cases, thefirst and second anhydride is the same and in one instance the first andsecond anhydride is acetic anhydride.

The first and second acid differ and each may be a carboxylic acid andmay be a C₂₋₂₄ carboxylic acid and mixtures thereof. In some cases theymay be a C₁₀ to C₂₄, carboxylic acid and mixtures thereof and in someinstances may be lauric acid, myristic acid, palmitic acid, stearicacid, arachidic acid, linoleic acid, linolenic acid, steridonic acid,oleic acid, and mixtures thereof. In some instances, the carboxylic acidis from lauric acid, stearic acid, oleic acid and mixtures thereof.

It is contemplated that the first and second carboxylic acid may besaturated or an unsaturated fatty acid. Advantageous examples of thefirst and second carboxylic acids include lauric acid, myristic acid,palmitic acid, stearic acid, arachidic acid, linoleic acid, linolenicacid, steridonic acid, oleic acid, and mixtures thereof. In someinstances the first and second carboxylic acid differ and are selectedfrom lauric acid, stearic acid, and oleic acid. As noted above, afterseparate formation of the first and second mixed acid anhydride, thefirst and second mixed acid anhydride may be mixed and thereafterreacted with the starch in the presence of a catalyst to form a starchmixed ester biodegradable and/or compostable composition.

In another embodiment, a first mixed acid anhydride, a second mixed acidanhydride, and a third mixed acid anhydride are separately formed and,after formation mixed together prior to reacting the mixture with astarch. In this regard, each of the first, second, and third mixed acidanhydride differ. In accord with this embodiment, a first anhydride anda first acid may be reacted to form a first mixed acid anhydride, asecond anhydride and a second acid may be reacted to form a second mixedacid anhydride, and a third anhydride and a third acid may be reacted toform a third mixed acid anhydride. While each of the first, second, andthird anhydride may differ, generally it is the same and, in thoseinstances where it is the same, it may be acetic anhydride.

In some instances, each of the first, second, and third acids may andeach may be a carboxylic acid and may be a C₂₋₂₄ carboxylic acid andmixtures thereof. In some cases they may be C₁₀ to C₂₄, and in someinstances they may be lauric acid, myristic acid, palmitic acid, stearicacid, arachidic acid, linoleic acid, linolenic acid, steridonic acid,oleic acid, and mixtures thereof. It is contemplated that the first,second, and third carboxylic acid may be saturated or an unsaturatedfatty acid. Advantageous examples of the first, second and thirdcarboxylic acids include lauric acid, myristic acid, palmitic acid,stearic acid, arachidic acid, linoleic acid, linolenic acid, steridonicacid, oleic acid, and mixtures thereof. In some instances the first,second, and third carboxylic acid differ and are selected from lauricacid, stearic acid, and oleic acid. As noted above, after separateformation of the first, second, and third mixed acid anhydride, thefirst, second, and third mixed acid anhydride may be mixed andthereafter reacted with the starch in the presence of a catalyst to forma starch mixed ester biodegradable and/or compostable composition.

Thereafter, the starch mixed ester biodegradable and/or compostablecomposition may be cured in water (which may be effective to separateunreacted acid anhydride and fatty acid), after which the cured productmay be pulverized, washed, neutralized, and dehydrated. The dehydratedproduct may then be dried to provide a dried product. In addition, it iscontemplated that the dried water washed product may be washed withalcohol, which will remove unreacted fatty acid, and then dried.Alternatively, the dehydrated product may be directed to an extruder forfurther processing optionally with additives or other biodegradableand/or compostable polymers, as will be explained in more detail below.As yet another alternative, it is contemplated that the water andalcohol washed product may be dried and then blended with one or morebiodegradable and/or compostable polymers.

Turning now to FIG. 3 , an alternative process for preparing a starchmixed ester biodegradable and/or compostable composition is shown. Inthis process, a starch, fatty acid, acid anhydride, and catalyst areprovided to a reactor and reacted for a period of time under suitableconditions to dehydrate the starch. Thereafter, additional fatty acidand acid anhydride are added for a period of time and under suitableconditions (e.g., from 0.5 to 4 hours at a temperature between about100° C. to about 140° C.) to esterify the starch and form a starch mixedester biodegradable and/or compostable composition.

The resulting product may be cured in water (which may be effective toseparate unreacted acid anhydride and fatty acid), after which the curedproduct may be pulverized, washed, neutralized, and dehydrated. Thedehydrated product may then be dried to provide a dried product. Inaddition, it is contemplated that the dried water washed product may bewashed with alcohol, which will remove unreacted fatty acid, and thendried. Alternatively, the dehydrated product may be directed to anextruder for further processing optionally with additives or otherbiodegradable and/or compostable polymers, as will be explained in moredetail below. As yet another alternative, it is contemplated that thewater and alcohol washed product may be dried and then blended with oneor more biodegradable and/or compostable polymers.

Turning now to FIG. 4 , a two-pot reaction scheme, i.e., a two reactorreaction scheme for making a starch mixed ester composition is shown.This process will be described using stearic acid, acetic anhydride, andsodium hydroxide as exemplars for each of the acid, acid anhydride, andcatalyst, respectively. In one reactor, acetic anhydride and starch aremixed with sodium hydroxide to dehydrate the starch and remove the waterfrom the sodium hydroxide solution and form acetic acid according to thefollowing reaction.

The reaction may be conducted for a period of time from about 1 hour toabout 48 hours or about 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33,34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, or 48 hours orany range that may be created from these values. The reaction may beconducted at a temperature from about 20° C. to about 35° C. or about21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, or about 35° C.or any range that may be created from these values.

In the other reactor, stearic acid and acetic anhydride are mixed andreacted under suitable conditions to form a mixed acid anhydride, i.e.,acetic anhydride, stearic acid, acetic stearic anhydride, acetic acid,and stearic anhydride as shown below in the following reaction schemes.

In this regard, suitable reaction conditions may include a reactiontemperature between about 80° C. to about 120° C., or about 90° C. toabout 110° C., or about 95° C. to about 105° C. To this end, thetemperature may be about 90° C., or about 91, 92, 93, 94, 97, 98, 99,100, 101, 102, 103, 104, 105, 106, 107, 108, 109, or about 110° C., orany range that may be created from these values.

Similarly, the time of reaction may be from about 15 minutes to about360 minutes, or about 30 minutes to about 300 minutes, or about 45minutes to about 240 minutes, or about 50 minutes to about 120 minutes,or about 55 minutes to about 90 minutes, or about 60 minutes. To thatend, the time of reaction may be from about 45, or about 46, 47, 48, 49,50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67,68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79. 80 81, 82, 83, 84, 85,86, 87. 88. 89 or about 90 minutes or any range that may be created fromthese values.

Thereafter, the mixed acid anhydride is mixed with the dehydrated starchand reacted under suitable conditions to form a starch mixed estercomposition. Suitable reaction conditions include reacting attemperature from about 125° C. to about 165° C., or from about 125, 126,127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140,141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154,155, 156, 157, 158, 159, 160, 161, 162, 163, 164, or about 165° C. orany range that may be created from these values. To that end the time ofreaction may be from about 1 to 15 hours or about 1, 2, 3, 4, 5, 6, 7,8, 9, 10, 11, 12, 13, 14, or about 15 hours or any range that may becreated from these values.

The starch mixed ester composition may then be washed with water toremove unreacted acetic anhydride, unreacted stearic acid, and aceticacid and then dried to form a water-washed starch mixed estercomposition. The dried water-starch mixed ester composition may befurther processed such as by pelletizing, forming into articles, and/orblending with other biodegradable and/or compostable polymers (andadditives), as shown and described in connection with FIGS. 1-3 .

In addition and alternatively, the dried starch mixed ester compositionmay be further washed with alcohol, which will remove the unreactedstearic acid remaining after the water washing, after which, the alcoholwashed starch mixed ester composition can be dried to form an alcoholwashed starch mixed ester composition. The dried alcohol-starch mixedester composition may be further processed such as by pelletizing,forming into articles, and/or blending with other biodegradable and/orcompostable polymers (and additives), as shown and described inconnection with FIGS. 1-3 . The removed unreacted acetic anhydride,unreacted stearic acid, and acetic acid from the water washing and theremoved unreacted stearic acid from the alcohol washing, if performed,may be sent to further processing or treatment for re-use or otherpurposes.

Turning now to FIG. 5 , a single pot reaction scheme, i.e., a singlereactor reaction scheme for making a starch mixed ester composition isshown. This process will be described using stearic acid, aceticanhydride, and sodium hydroxide as exemplars for each of the acid, acidanhydride, and catalyst, respectively. In the reactor, acetic anhydrideand starch are mixed with an aqueous solution of sodium hydroxide todehydrate the starch, remove the water from the sodium hydroxidesolution by reaction to form acetic acid.

Suitable reaction conditions include reacting at a temperature of aboutfrom about 20° C. to about 35° C. or about 21, 22, 23, 24, 25, 26, 27,28, 29, 30, 31, 32, 33, 34, or about 35° C. or any range that may becreated from these values. The reaction may be conducted for a period oftime ranging from about 1 minute to about 60 minutes, or about 5 minutesto about 30 minutes or about 10 minutes to about 20 minutes or about 15minutes. In some instances, the reaction may be conducted for a periodof time of about 5 minutes or about 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,16, 17, 18, 19, 20, 21, 22, 23, 24, or about 25 minutes or any rangethat may be created from these values.

Based on 100 grams of cornstarch (in some instances, high amylosecornstarch), which is about 0.62 mol, the amount of acetic anhydrideadded to the reactor will be about 1.0 mol to about 2.0 mol, or about1.0, 1.1, 1.2, 1.3. 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or about 2.0. Theamount of sodium hydroxide added to the reactor will be from about 0.05mol to about 0.15 mol, or about 0.06, 0.07, 0.08, 0.09, 0.10, 0.11,0.12, or about 0.15.

Upon completion of the reaction, i.e., at the end of the reaction timenoted above, stearic acid and an additional amount of and aceticanhydride are added to the reactor and reacted under suitable conditionsto form a starch mixed ester composition. In this regard, the amount ofstearic acid will be about 0.1 to about 0.6 mol, or about 0.1, 0.3, 0.4,0.5, or about 0.6 mol. The amount of additional acetic anhydride addedto the reactor may be from about 0.5 mol to 1.5 mol or about 0.5, 0.6,0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, or about 1.5 mol.

Based on the foregoing, the skilled artisan will appreciate that where agreater amount of cornstarch is used, the amounts of the aceticanhydride (in each of the dehydration and esterification steps), sodiumhydroxide, and stearic acid will be increased accordingly.

Suitable reaction conditions may include a reaction temperature betweenabout 100° C. to about 180° C., or about 110° C. to about 170° C., orabout 115° C. to about 160° C. To this end, the temperature may be about100° C., or about 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111,112, 113, 114, 115, 116, 117, 118, 119, 120, 121,122, 123, 124, 125,126, 127,128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139,140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153,154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167,168. 169, 170, 171, 172, 173, 174, 175, 176, 177. 178, 179, or about180° C., or any range that may be created from these values.

The time of reaction may be from about 30 minutes to about 360 minutes,or about 60 minutes to about 300 minutes, or about 90 minutes to about240 minutes, or about 100 minutes to about 180 minutes, or about 110minutes to about 150 minutes, or about 120 minutes. To that end, thetime of reaction may be from about 100 minutes, or about 101, 102, 103,104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117,118, 119, 120, 121,122, 123, 124, 125, 126, 127,128, 129, 130, 131, 132,133, 134, 135, 136, 137, 138, 139, or about 140 minutes, or any rangethat may be created from these values.

The starch mixed ester composition is then washed with water to removeunreacted acetic anhydride, unreacted stearic acid, and acetic acid andthen dried to form a water-washed starch mixed ester composition. Thedried water-starch mixed ester composition may be further processed suchas by pelletizing, forming into articles, and/or blending with otherbiodegradable and/or compostable polymers (and additives), as shown anddescribed in connection with FIGS. 1-3 .

In addition and alternatively, the dried starch mixed ester compositionmay be further washed with alcohol, which will remove the unreactedstearic acid remaining after the water washing, after which, the alcoholwashed starch mixed ester composition can be dried to form an alcoholwashed starch mixed ester composition. The dried alcohol-starch mixedester composition may be further processed such as by pelletizing,forming into articles, and/or blending with other biodegradable and/orcompostable polymers (and additives), as shown and described inconnection with FIGS. 1-3 . The removed unreacted acetic anhydride,unreacted stearic acid, and acetic acid from the water washing and theremoved unreacted stearic acid from the alcohol washing, if performed,may be sent to further processing or treatment for re-use or otherpurposes.

Blends of Starch Mixed Esters with Other Biodegradable and/orCompostable Polymers

As intimated above, it is contemplated that the described starch mixedester biodegradable and/or compostable compositions may be blended withone or more other biodegradable and/or compostable polymers to form ablend composition. The blends may be prepared by mixing or meltprocessing using an extruder or similar apparatus, as indicated in FIGS.1-3 .

In this regard, the blend may include from about 20% to about 90% of thedescribed starch mixed ester composition and from about 10% to about 80%of at least one other biodegradable and/or compostable polymer. Forexample, the described starch mixed ester composition may be present inthe blend in an amount of about 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, or about 90%. The at least one otherbiodegradable and/or compostable polymer may be present in the blend inan amount of about 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, or about 80%.

With respect to the starch mixed ester composition, it is contemplatedthat the starch mixed ester composition that is blended with the otherbiodegradable and/or compostable polymer may be the starch mixed estercomposition prior to water washing, after water washing, or afteralcohol washing. In each instance, the starch mixed ester compositionwill typically be dried prior to blending. In those instances where thestarch mixed ester composition is blended after water washing anddrying, the amount of unreacted fatty acid (e.g. stearic acid) may be ina range from about 20% to about 40% with respect to the starch mixedester composition. To this end, the amount of unreacted fatty acid (e.g.stearic acid) present in the starch mixed ester composition may be about20%, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 36, 37. 38,39, or about 40%

The at least one other biodegradable and/or compostable polymer in theblend may be a starch biodegradable and/or compostable polymer and mayalso include biodegradable and/or compostable polymers such aspolylactide (PLA), poly(hydroxybutyrate) (PHB), polycaprolactone (PCL),polyhydroxy butyrate valerate (PHB-V), poly(β-hydroxyalkanoate) (PHA),Poly(1,4-butylene succinate) (PBS), polybutylene adipate terephthalate(PBAT), poly(vinyl alcohol) (PVA), cellulose-based ester derivatives ora mixture thereof.

In some aspects, the at least one other biodegradable and/or compostablepolymer may be a linear polyester derived from hydroxyl-carboxylic acidsthat have the general formula:

HO—(C_(n)H_(2n))—COOH  (1)

where n is an integer from 1 to 21, preferably an integer from 1 to 7,and more preferably is 1, 2, 3, 4 or 5.

Such acids are for example glycolic acid (n=1), lactic acid (n=2 andwherein the hydroxyl group is fixed in the alpha-position), hydroxybutyric acid and hydroxy isobutyric acid (n=3), hydroxy valeric acid(n=4), hydroxy caproic acid (n=5) where in each case the hydroxy groupis fixed in the terminal position.

Methods for the preparation of linear polyesters of the type as derivedfrom such hydroxy-carboxylic acid are known in the art. Many of thesehydroxy-carboxylic acids are known to form a cyclic ester, i.e. alactone, which is preferably used for producing the correspondingpolyester. Hydroxy-caproic acid for example forms a cyclic ester knownas 6-caprolactone, which can be polymerized as such. Such lactones areknown. Preferred from such polylactones is poly(6-caprolactone).

The linear polyesters, derived from the combination of a diacid and adiol, as used in the present invention may be described by the followingformula:

where R is an aliphatic hydrocarbon residue with 2, 4 or 6 carbon atoms;and R′ is an aliphatic saturated or unsaturated divalent hydrocarbonresidue with 2 to 22 carbon atoms.

Examples of suitable linear polyesters can be described by the followingformula:

wherein x is 2 (poly(ethylene succinate)) or x is 4 (polyethyleneadipate)). The linear polyesters as used in the present invention maybe, as mentioned, derived from a hydroxy-carboxylic acid or a mixture ofsuch acids or from a corresponding lactone or a mixture of suchlactones. The linear polyesters may also be a physical mixture ofdifferent polyester types. Examples of such linear polyesters includepoly(3-propiolactone), poly(5-valerolactone), poly(6-caprolactone),poly(6-decalactone), poly(7-enamtholactone), poly(8-caprylolactone),poly(12-laurolactone), poly(15-pentadodecanolactone),poly(hydroxybutyrate), poly(hydroxyvalerate).

It is contemplated that a plasticizer may be added to the blendcomposition to provide greater material processability and productflexibility. Molded articles and films prepared from the blendcompositions may be modified by mixing with a variety of lowmolecular-weight ester plasticizers of the solvent type. An obviousrequirement of these plasticizers is that they are biodegradable and/orcompostable. Examples of such plasticizers include a variety of esters,such as phthalate esters (dimethyl-, diethyl-, dipropyl-, dibutyl-,dihexyl-, diheptyl-, dioctyl-, etc.), dimethyl- and diethylsuccinate andrelated esters, glycerol triacetate (triacetin), glycerol mono- anddiacetate, glycerol mono-, di and tripropionate, glycerol tributanoate(tributyrin), glycerol mono- and dibutanoate, glycerol mono-, di- andtristearate, and other related glycerol esters, lactic acid esters,citric acid esters, adipic acid esters, stearic acid esters, oleic acidesters, ricinoleic acid esters, other fatty acid esters, erucic acidesters, soybean oil, castor oil, and various other biodegradable and/orcompostable esters known in the chemical arts.

Inorganic and organic fillers may be included in the blend compositionsto extend the range of properties of molded articles. Such inorganicfillers may include talc (hydrous magnesium silicate), titanium dioxide,calcium carbonate, clay, sand, chalk, limestone, diatomaceous earth,silicates, boron nitride, mica, glass, quartz, and ceramics, andbiodegradable and/or compostable organic fillers such as starch,cellulose, wood flour and fibers, pecan fibers, and other well-knowninorganic and organic filler materials.

As noted above the blends may be formed by extruding together the starchmixed ester composition with a biodegradable and/or compostable polymerand additives to create, for example, pellets of the blend, which canthen be formed into articles or manufacture such as films and othermolded articles.

Articles of Manufacture

It is contemplated that the starch mixed ester biodegradable and/orcompostable compositions and the blends of the starch mixed esterbiodegradable and/or compostable compositions and one or more otherbiodegradable and/or compostable polymers may be processed by variousmethods known in the art such as, but not limited to, extrusion,injection molding, compression molding, filming, blow molding, vacuumforming, thermoforming, extrusion molding, co-extrusion, foaming,profile extrusion, combinations thereof, as well as other known andcontemplated methods. In this regard, it is contemplated that the starchmixed ester compositions may be formed into articles such as, but notlimited to, inks, paints, compost bag, laminate bags, agriculturalfilms, binder for earthenware, landscape piles or spikes, bottles,strands, sheets, films, packaging materials, pipes, tubes, lids, cups,rods, laminated films, sacks, bags, cutlery, pharmaceutical capsules,foams, granulates and powders.

The starch mixed ester compositions and the blends of the starch mixedester compositions and one or more other biodegradable and/orcompostable polymers may also find application as

-   -   (7) Films and sheet formed by extrusion, casting, rolling,        inflation, etc.    -   (8) Lamination and coatings on paper, sheet, film, nonwoven        fabric, etc.    -   (9) Additives to be incorporated into paper during the paper        making process to impart special functions to the paper and        paper products.    -   (10) Additives to be incorporated into non-woven fabric during        its manufacturing process to impart special functions to the        non-woven fabrics and their products.    -   (11) Aqueous emulsions or suspensions for use with paints, inks,        and the like.    -   (12) Solid molded products such as landscaping piles produced by        injection molding, extrusion molding, blow molding, transfer        molding, compression molding, etc.

The following examples may provide additional details about thedescribed composition and methods in accordance with this disclosure.

Example 1

225 g of acetic anhydride and 150 g of lauric acid were placed in a 1 Lseparable flask, heated, and stirred at 60° C. for 2 h to produceacetic-lauric anhydride, which thereafter was combined with 150 g ofhigh amylose corn starch (having an amylose content of about 75%) todisperse the corn starch. Thereafter, 51.8 g of a catalyst in the formof 35% sodium hydroxide was added. The temperature was increased to 145°C. and the mixture was stirred for 4 h while refluxing. Thereafter, themixture was cooled to 120° C. and 225 g of acetic anhydride 225 g wasadded and the mixture was stirred at 130° C. for 1 h.

The obtained viscous liquid was put into water and cured. The cured masswas pulverized in water and pulverization was repeated several times toproduce small particles. After washing with water, the product wasre-slurried and neutralized from pH 4 to pH 7 with sodium hydroxide. Theneutralized product was dehydrated and dried at ° C. overnight. Thedried powder was re-slurried in ethanol, unreacted lauric acid waswashed and removed, and the target compound was recovered by suctionfiltration. This operation was repeated twice to remove lauric acid.

The recovered product was pulverized in water, washed with water,dehydrated, and dried at 80° C. to obtain the desired starch mixed estercomposition.

Example 2

High amylose corn starch (having an amylose content of about 75%) wasmixed with an amount of acetic anhydride to provide about two moles ofacetic anhydride for each mole of water in the high amylose starch. Themixture was stirred for 24 hours to remove the water in the starch. Theproduct was suction-filtered and dried under reduced pressure in adesiccator for 24 hours.

Stearic acid (200 g) and acetic anhydride (200 g) were mixed withstirring at 100° C. for one hour to form a mixed acid anhydride. Themixed acid anhydride was cooled to 60° C. and mixed with the dried highamylose starch, after which a catalyst, DMAP (12 g) dissolved in aceticanhydride (50 g), was added in a dropwise fashion of about 2-3drops/second.

After completion of the catalyst addition, the temperature was increasedto 145° C. and the reaction was carried out with stirring for fourhours. Thereafter, the mixture was cooled to 60° C. to permit theaddition of additional acetic anhydride (150 g), upon completion ofwhich the temperature was increased back to 145° C. and the reactioncontinued with stirring for another four hours, at which time thereaction was considered complete.

After completion of the reaction, the temperature was reduced to 60° C.,and the viscous reaction product was placed into 60° C. water to cure(solidify) the reaction product, which thereafter was then pulverized,filtered, and dehydrated to obtain the desired starch mixed estercomposition.

Example 3

High amylose corn starch (having an amylose content of about 75%) wasmixed with NaOH and an amount of acetic anhydride to provide about twomoles of acetic anhydride for each mole of water in the high amylosestarch. The mixture was stirred for 24 hours to remove the water in thestarch.

Stearic acid (100 g) and acetic anhydride (100 g) were mixed withstirring at 100° C. for one hour to form a mixed acid anhydride. Highamylose corn starch with acetic anhydride and a 50% aqueous solution ofNaOH were heated up to 60° C. and the mixed acid anhydride was added.After completion of the mixed acid anhydride addition, the temperaturewas increased to 120° C. and the reaction was carried out with stirringfor seven hours at which time the reaction was considered complete.

After completion of the reaction, the viscous reaction product wasplaced into water to cure (solidify) the reaction product, whichthereafter was pulverized, filtered, and dehydrated to obtain thedesired mixed ester composition. The obtained viscous liquid was putinto water and cured. The cured mass was pulverized in water andpulverization was repeated several times to produce small particles.After washing with water, the product was re-slurried with water untilthe pH reached between about 6 to about 7. The neutralized product wasdehydrated and dried at 80° C. overnight. The dried powder wasre-slurried in ethanol, unreacted stearic acid was washed and removed,and the target compound was recovered by suction filtration. Thisoperation was repeated twice to remove stearic acid.

Several batches of the starch mixed ester composition were madeaccording to the method described in Example 3 and the glass transitiontemperature and degree of substitution (DS) was measured. Table 1 showsthe results.

TABLE 1 Glass transition DS of DS of DS of total DS of total Sampletemperature stearate acetate ester ester lot Catalyst (° C.) (by NMR)(by NMR) (by NMR) (by titration) 2022J1 DMAP 156.3 0.043 2.41 2.45 2.82022J2 NaOH 147.1 0.043 2.56 2.60 2.7 230126 NaOH 144.2 0.026 2.29 2.322.2 230221 NaOH 146.0 2.0 230223 NaOH 148.7 2.3 230301 NaOH 137.8 2.4230303 NaOH 147.2 1.8 230308 NaOH 144.7 2.0 230310 NaOH 144.2 2.2 230313NaOH 141.0 1.9

Example 4

The method of Example 3, described above, was repeated except that thestearic acid was replaced with either oleic acid or lauric acid (withthe same number of moles as stearic acid). The glass transitiontemperature and degree of substitution (DS) was measured. Table 2 showsthe results.

TABLE 2 Glass transition DS of total ester Sample Catalyst temperature(° C.) (by titration) Starch Acetate Oleate NaOH 145.5 2.8 StarchAcetate Laurate NaOH 146.8 2.7

Example 5

Starch mixed ester compositions were prepared according to the processshown in FIG. 5 and described above. Table 3 presents data relating tothe tested conditions and the analysis of the resulting starch mixedester compositions.

TABLE 3 Data Analysis DS by NMR Reaction conditions Total DS Reaction DSby ST or scale TGA titration DS Ol Acid Carboxylic (starch Washing peakT_(g) MFR (Cal. as or DS No. Starch anhydride acid g) process (° C.) (°C.) (2.16 kg) DS Ac) DS Ac LA 1 HACS Ac₂O Stearic 100 Water 204.3/79.3/133.12 43.7 (190° C.) — — — acid wash 362.5  6.2 (170° C.) 2 HACS Ac₂OStearic 100 Ethanol 359.3 143.45 10.4 (190° C.) 2.0 2.03 0.04 acid wash3 HACS Ac₂O Stearic 3000 Water 149.7/230.1/ 107.89 — — — — acid wash351.9 4 HACS Ac₂O Stearic 3000 Ethanol 356.5 146.34 — 1.87 1.80 0.06acid wash 5 Corn Ac₂O Stearic 100 Water 190.3/259.9/ — — — — — starchacid wash 361.3 6 Corn Ac₂O Stearic 100 Ethanol 360.8 146.21 — 1.76 1.770.08 starch acid wash 7 HACS Ac₂O Oleic 100 Water 278.5/347.0 N/A — — —— acid wash 8 HACS Ac₂O Oleic 100 Ethanol 355.0 147.9 — 1.97 2.06 0.06acid wash 9 HACS Ac₂O Lauric 100 Water 291.3/351.1 111.1 — — — — acidwash 10 HACS Ac₂O Lauric 100 Ethanol 361.8 140.9 — 2.05 2.07 0.06 acidwash 11 HACS Ac₂O — 100 Water 356.1 151.6 — 2.15 1.78 0 wash Reactioncondition: No. 1-4, 7-11: at 120° C. for 2H, No. 5-6: at 160° C. for 2HHACS: High amylose cornstarch; ST: Stearate; OL: Oleate; LA: Lauric Acid

Example 6

Starch mixed ester compositions were prepared according to the processshown in FIG. 5 and described above. Thermogravimetric analyses (TGA)were performed on a sample of a starch acetate stearate that was madeaccording to the method shown and described in connection with FIG. 5 .Referring to FIG. 6A, a thermogravimetric analysis (TGA) was performedon a sample of a starch acetate stearate that was made and water washedaccording to the method shown and described in connection with FIG. 5 .FIG. 6B shows the results of a thermogravimetric analysis (TGA)performed on a sample of a starch acetate stearate that was made andethanol washed according to the method shown and described in connectionwith FIG. 5 . FIG. 6C shows the results of a thermogravimetric analysis(TGA) performed on a sample of a high amylose cornstarch that was usedto make the starch acetate stearate tested in FIGS. 6A and 6B.

¹H-NMR analyses were performed on a sample of a starch acetate stearatethat was made according to the method shown and described in connectionwith FIG. 5 . The samples for NMR (nuclear magnetic resonance)measurements were prepared by dissolving ˜30 mg of the sample in 0.7 mlDMSO-d₆, and the mixture was transferred to a 5 mm NMR tube using aglass Pasteur pipette. The NMR measurements were performed at 50° C. ona Bruker Advance Spectrometer (500 MHz). The residual DMSO signal wastaken as an internal reference in the measurements.

FIG. 7A shows the ¹H-NMR analysis of a sample of a starch acetatestearate that was made and water washed according to the method shownand described in connection with FIG. 5 . The resonances of the starchbackbone, anomeric proton and unsubstituted hydroxyl groups (denoted1-9) can be observed in the region 3.3-5.9 ppm. The signal correspondingto the methine protons of stearic acid (denoted 13-26) are observedaround 1.24 ppm. The signals corresponding to the methyl protons ofstearic acid (denoted 27) and acetic anhydride (denoted 10) are observedat and in the region 1.8-2.3 ppm, respectively. In addition, there is abroad signal appearing in the region 10.7-12.8 ppm, which corresponds tothe carboxylic acid group (denoted *) of stearic acid. This confirms thepresence of unreacted stearic acid in the water washed sample.

FIG. 7B shows the ¹H-NMR analysis of a sample of a starch acetatestearate that was made and ethanol washed according to the method shownand described in connection with FIG. 5 . The resonances of the starchbackbone, anomeric proton and unsubstituted hydroxyl groups (denoted1-9) can be observed in the region 3.3-5.9 ppm. The signal correspondingto the methine protons of stearic acid (denoted 13-26) is observed at1.24 ppm. The signals corresponding to the methyl protons of stearicacid (denoted 27) and acetic anhydride (denoted 10) are observed at 0.84and in the region 1.8-2.3 ppm, respectively. In addition, the broadsignal corresponding to the carboxylic acid group is lost in the ethanolwashed sample, which confirms the removal of unreacted stearic acidafter ethanol washing of starch acetate stearate.

FIG. 7C shows the ¹H-NMR analysis of a sample of a high amylosecornstarch used to make the starch acetate stearate tested in of FIGS.7A and 7B. The resonances of the starch chain protons (denoted 2-6) canbe readily identified in the region 3.5-3.9 ppm. The anomeric proton(denoted 1) corresponding to the internal α-1,4 linkages, and the methylproton corresponding to the OH groups of starch (denoted 7-9) are foundin the region 4.25-5.5 ppm. The signal of the residual water peak ispresent at 3.28 ppm, which appears due to the hygroscopic nature of bothstarch and DMSO.

¹³C-NMR analyses were performed on a sample of a starch acetate stearatethat was made according to the method shown and described in connectionwith FIG. 5 . The samples for NMR (nuclear magnetic resonance)measurements were prepared by dissolving ˜30 mg of the sample in 0.7 mlDMSO-d₆, and the mixture was transferred to a 5 mm NMR tube using aglass Pasteur pipette. The NMR measurements were performed at 50° C. ona Bruker Advance Spectrometer (500 MHz). The residual DMSO signal wastaken as an internal reference in the measurements.

FIG. 8A shows the ¹³C-NMR analysis of a sample of a starch acetatestearate that was made and water washed according to the method shownand described in connection with FIG. 5 . As observed from the ¹³C-NMRspectrum, the signals corresponding to the starch backbone and anomericcarbon are observed in the region 60-98 ppm (denoted 1 and 2-4). Thesignals attributed to the secondary carbon of the alkyl chain of stearicacid (denoted 11-26) are observed in the region 21.2-34.3 ppm. Further,the signals corresponding to the primary carbon of stearic acid (denoted27) and acetic anhydride (denoted 10) are observed at 13.7 and 20.2 ppm,respectively. The resonances of carbonyl carbon of the stearic acid(denoted 28) and acetic anhydride (denoted 30) are observed at 169.1 and169.8 ppm, respectively. Additionally, the signal at 174.1 ppm isattributed to the carboxylic acid group (denoted *) present in stearicacid, which also confirms the presence of unreacted stearic acid in thewater washed sample.

FIG. 8B shows the ¹³C-NMR analysis of a sample of a starch acetatestearate that was made and ethanol washed according to the method shownand described in connection with FIG. 5 . As observed from the ¹³C-NMRspectrum, the signals corresponding to the starch backbone and anomericcarbon are observed in the region 60-98 ppm (denoted 1 and 2-4). Thesharp signals attributed to secondary carbons of the alkyl chain ofstearic acid (denoted 14-24) are observed around 28.7 ppm. Further, thesignals corresponding to the primary carbon of stearic acid (denoted 27)and acetic anhydride (denoted 10) are observed at 13.7 and 20.2 ppm,respectively. The resonances of carbonyl carbon of the stearic acid(denoted 28) and acetic anhydride (denoted 30) are observed at 169.1 and169.8 ppm, respectively. Additionally, the signal corresponding to thecarboxylic acid group of stearic acid is lost, which in turn confirmsthe removal of unreacted stearic acid upon ethanol washing of starchacetate stearate.

FIG. 8C shows the ¹³C-NMR analysis of a sample of a high amylosecornstarch used to make the starch acetate stearate tested in of FIGS.8A and 8B. As observed from the ¹³C-NMR spectrum, the resonances of thestarch chain carbons (denoted 2-6) are identified in the region 60-80ppm. The anomeric carbon (denoted 1) corresponding to the internal α-1,4linkages is observed around 100 ppm.

Example 8

A blend of starch acetate stearate and PBAT was produced in thefollowing manner. PBAT was fed at a feed rate of 1 kg/hr into amulti-zone Leistritz twin screw extruder operating with a screw speed ofabout 100 rpm. The extruder had the following temperature profile: 145°C./155° C./180° C./180° C./185° C./185° C./180° C./180° C./160° C./145°C., with a die temperature of 131° C. After feeding the PBAT for aperiod of time (between about 15 to 20 minutes), feed of a water washed(and dried) starch acetate stearate composition was started at a feedrate of 1 kg/hr. The blend exiting the die, which containedapproximately equal parts of the starch acetate stearate and PBAT, wascollected and delivered to a water bath with samples being collectedafter about 7-10 minutes, 10-20 minutes, and 20-25 minutes. Thereafter,the blend was pelletized. Each of the samples were analyzed usingthermogravimetric analysis (TGA), derivative thermogravimetric analysis(DTG), and differential scanning calorimetry (DSC) with the resultsshown in Tables 4 and 5. Thereafter, the blends were pelletized.

Example 9

The blend described in Example 8 was repeated except the feed rate wasadjusted to feed the starch acetate stearate composition at about 0.6kg/hr and the PBAT at about 1.4 kg/hr so that a blend containing about30% starch acetate stearate and about 70% PBAT was formed. As withExample 8, the blend exiting the die was collected and delivered to awater bath with samples being collected after about 20-30 minutes.Thereafter, the blend was pelletized. The samples were analyzed usingthermogravimetric analysis (TGA), derivative thermogravimetric analysis(DTG), and differential scanning calorimetry (DSC) with the resultsshown in Tables 4 and 5.

TABLE 4 TGA weight loss (%) & DTG peak temperature Peak 1 Peak 2 Peak 1,2 Peak 3 Peak 4 Peak 3, 4 DTG DTG Weight DTG DTG Weight peak peak changepeak peak change Sample (° C.) (° C.) (%) (° C.) (° C.) (%) SAS/PBAT50:50 210.91 — 17.65 368.26 392.93 74.62 7-10 min SAS/PBAT 50:50 212.29283.99 20.83 364.15 391.89 70.75 10-20 min SAS/PBAT 50:50 219.48 290.5219.42 364.85 397.27 71.55 20-25 min SAS/PBAT 30:70 207.11 — 11.08 357.44390.59 81.38 20-30 min PBAT — — — — 396.89 — SAS (water wash) 199.17291.51 37.53 355.17 — 49.47 SAS (Ethanol wash) — — — 357.29 — Stearicacid 235.96 — — — — —

TABLE 5 Sample Tg (° C.) Tm 1 (° C.) Tm 2 (° C.) SAS/PBAT 50:50 7-10 min— 69.39 127.01 SAS/PBAT 50:50 10-20 min — 69.61 126.13 SAS/PBAT 50:5020-25 min — 69.53 125.55 SAS/PBAT 30:70 20-30 min — 68.91 129.06 PBAT —— 127.07 SAS (water wash) 122.62 — — SAS (Ethanol wash) 142.78 — —Stearic acid — 71.71 —

Example 10

A 120 second Cobb test was performed according to ASTM D3285-93(Standard Test Method for Water Absorptiveness of Nonbibulous Paper andPaperboard) was performed Kraft paper (86 gsm) alone and coated (using arod coating method) with high amylose corn starch, cornstarch, starchacetate, a water washed starch acetate stearate made according to themethod shown and described with respect to FIG. 5 , where the starch wasa high amylose cornstarch, an ethanol washed starch acetate stearatemade according to the method shown and described with respect to FIG. 5, where the starch was a high amylose cornstarch, a water washed starchacetate stearate made according to the method shown and described withrespect to FIG. 5 , where the starch was a normal (not high amylose)cornstarch, an ethanol washed starch acetate stearate made according tothe method shown and described with respect to FIG. 5 , where the starchwas a normal (not high amylose) cornstarch, and PLA. The PLA coatingsolution was prepared by mixing the PLA with ethyl acetate to form a 5%(wt/vol) solution of PLA in ethyl acetate. The other coating solutionswere prepared by mixing the sample in acetonitrile to form a 5% (wt/vol)solution of sample in acetonitrile.

The results are shown in FIG. 9 and it can be observed that the each ofthe starch mixed ester biodegradable and/or compostable compositionsachieved Cobb values similar to PLA when the coat weight was about 3 to5 g/m². In addition, it can be appreciated that there was little to nodifference between the Cobb values when comparing the water washedstarch mixed ester biodegradable and/or compostable composition with theethanol starch mixed ester biodegradable and/or compostable compositionand when comparing the starch mixed ester biodegradable and/orcompostable composition made with high amylose starch and made withnormal corn starch.

While the concepts of the present disclosure are susceptible to variousmodifications and alternative forms, specific exemplary embodiments ofthe disclosure have been shown by way of example in the drawings. Itshould be understood, however, that there is no intent to limit theconcepts of the present disclosure to the particular disclosed forms;the intention is to cover all modifications, equivalents, andalternatives falling within the spirit and scope of the invention asdefined by the claims.

1. A biodegradable and/or compostable product or film prepared from abio-based starch mixed ester biodegradable and/or compostablecomposition comprising a mixed starch mixed ester having a total degreeof substitution of at least 1.0, wherein the ester substituents includea mixture of (a) acetate and (b) one or more C₁₀ to C₂₄ ester residues,wherein the degree of substitution of (a) is greater than (b).
 2. Thebiodegradable and/or compostable product or film according to claim 1wherein the composition further includes a plasticizer.
 3. Thebiodegradable and/or compostable product or film according to claim 1wherein the composition further includes a filler.
 4. The biodegradableand/or compostable product or film according to claim 1 wherein the oneor more C₁₀ to C₂₄ ester residues are selected from the group consistingof laurate, stearate, oleate, or mixtures thereof.
 5. The biodegradableand/or compostable product or film according to claim 1 wherein thecomposition has a glass transition temperature between about 125° C. toabout 165° C.
 6. The biodegradable and/or compostable product or filmaccording to claim 1 wherein the starch mixed ester has a total degreeof substitution between 1.5 to about 2.9.
 7. The biodegradable and/orcompostable product or film according to claim 1 wherein the product isan ink, paint, compost bag, laminate bag, agricultural film, binder forearthenware, landscape pile, spike, bottle, strand, sheet, packagingmaterial, pipe, tube, lid, cup, rod, laminated film, sack, bag, cutlery,pharmaceutical capsule, foam, granulate, or powder.
 8. The biodegradableand/or compostable product or film according to claim 1 wherein thebio-based starch mixed ester biodegradable composition further comprisesa biodegradable polymer other than the bio-based starch mixed ester. 9.The biodegradable and/or compostable product or film according to claim8 wherein the one or more C₁₀ to C₂₄ ester residues are selected fromthe group consisting of laurate, stearate, oleate, or mixtures thereof.10. The biodegradable and/or compostable product or film according toclaim 8 wherein the composition has a glass transition temperaturebetween about 125° C. to about 165° C.
 11. The biodegradable and/orcompostable product or film according to claim 8 wherein the starchmixed ester has a total degree of substitution between 1.5 to about 2.9.12. The biodegradable and/or compostable product or film according toclaim 8 wherein the bio-based starch mixed ester comprises from about20% to about 90% of the blend and the biodegradable polymer other thanthe bio-based starch mixed ester comprises from about 10% to about 80%of the blend.
 13. The biodegradable and/or compostable product or filmaccording to claim 8 wherein the biodegradable polymer other than thebio-based starch mixed ester is selected from the group consisting ofpolylactide (PLA), poly(hydroxybutyrate) (PHB), polycaprolactone (PCL),polyhydroxy butyrate valerate (PHB-V), poly(β-hydroxyalkanoate) (PHA),Poly(1,4-butylene succinate) (PBS), polybutylene adipate terephthalate(PBAT), poly(vinyl alcohol) (PVA), cellulose-based ester derivatives ora mixture thereof.